The present invention relates to a hydraulic unit for a slip-controlled brake system with an accommodating member accommodating inlet and outlet valves in several valve accommodating bores of a first and a second valve row. The hydraulic unit has a pump bore which is arranged outside the two valve rows in the accommodating member and is aligned transversely to the direction of the valve accommodating bores opening into the accommodating member.
Two low-pressure accumulator bores open into the accommodating member outside the two valve rows and vertically to the axes of the valve accommodating bores and the pump bore. At least one hollow-cylinder-shaped noise damping chamber connected to the pump bore is arranged in parallel to the pump bore in a housing plane which is arranged in parallel to a housing plane that includes the valve accommodating bores. The hydraulic unit also includes several pressure fluid channels connecting the valve accommodating bores, pump bores and low-pressure accumulator bores and is adapted to establish a hydraulic connection between the brake pressure generator connections that open into the accommodating member and the wheel brake connections for the transport of pressure fluid.
A hydraulic unit of the type mentioned above is disclosed in DE 195 42 582 A1. It is proposed in this application to arrange the noise damping chamber in parallel to the pump bore in the accommodating member and to connect the pump bore to the noise damping chamber by way of a channel, to what end the channel opens radially into the wall of the noise damping chamber. To connect the noise damping chamber to at least one of the wheel brake connections of the accommodating member, an additional channel is provided which opens radially into the peripheral surface of the noise damping chamber and leads to at least one of the wheel brake connections.
The chosen arrangement of the channels impairs, however, complete rinsing of the noise damping chamber for the purpose of optimal bleeding.
In view of the above, an object of the invention is to improve a hydraulic unit of the mentioned type using means which are as simple as possible in such a manner that the shortcoming referred to hereinabove is overcome.